Non-Markovian Dynamics of Quantum Discord

TL;DR

This paper investigates how quantum discord and entanglement evolve over time in two qubits interacting with non-Markovian environments, revealing distinct behaviors such as sudden death and birth, and sudden changes in dynamics.

Contribution

It provides a detailed comparison of quantum discord and entanglement dynamics in non-Markovian settings, highlighting unique phenomena like discord sudden birth and derivative discontinuities.

Findings

Quantum discord vanishes only at discrete times in independent reservoirs.

Entanglement can disappear over finite time intervals.

Quantum discord can exhibit sudden birth and abrupt changes in its evolution.

Abstract

We evaluate the quantum discord dynamics of two qubits in independent and common non-Markovian environments. We compare the dynamics of entanglement with that of quantum discord. For independent reservoirs the quantum discord vanishes only at discrete instants whereas the entanglement can disappear during a finite time interval. For a common reservoir, quantum discord and entanglement can behave very differently with sudden birth of the former but not of the latter. Furthermore, in this case the quantum discord dynamics presents sudden changes in the derivative of its time evolution which is evidenced by the presence of kinks in its behavior at discrete instants of time.